A study by Grandjean, et. al. for the Department of Hygiene and Ergonomics of the Swiss Federal Institute of Technology in 1982 examined workers performance using standard keyboards for use with video display terminals manufactured by IBM and Raytheon. The keyboards were standard models having a home row height of 80 mm above the desk level. A forearm-wrist support that was flat and fixed at an 18.degree. angle was provided the workers. The study reports that 83% of the subjects rested their forearms when the device was present; however, over half the subjects rested their wrists when no such device was present. When asked to judge the comfort related to the forearm support, 80% indicated the presence of the forearm-wrist support was comfortable, while 3% found it uncomfortable. To rest the hands on the desk surface was found comfortable by 52% of the subjects and uncomfortable by 21% of the subjects.
The present invention is designed to provide support to the forearm and to overcome several disadvantages to the forearm-wrist support used in the Grandjean et. al. study. The design of the present invention comprises a forearm rest which, preferably, comprises cushion means having a surface designed to support the forearm during keyboard activities, means to adjust the position of the cushion means to provide a variable distance from the keyboard and cushion means to accommodate the largest number of users and keyboards, means for tilting the cushion means to a desired angle and means to support the forearm rest on the work surface supporting the keyboard and means to keep the rest from sliding with respect to such work surface during use of the keyboard. The cushion means is made of a rigid member covered by padded material and is hinged so as to tilt with respect to the horizontal and thereby accommodate various keyboard thicknesses and users of different sizes. The angle of tilt is variable between horizontal and a maximum angle selected for comfort. Additionally, the upper surface of the hinged, padded cushion means of the present invention is rolled at the edges and slopes outwardly to each side from a raised center plateau providing a raised center portion and to either side of the centerline of this raised center portion a sloping surface and a flat outer surface. The sloping surface begins at either side of the raised center portion and extends forward, i.e. away from the keyboard, at an outward angle to the centerline of the rest to conform the surface of the forearm rest to the natural resting position of the forearms when the hands are placed in the home row position on the keyboard. Additionally, in the preferred embodiment, these sloping surfaces have a larger surface area at the forward portion thereof, i.e., away from the keyboard. The configuration of this sloping surface is an important characteristic of the present invention. If one observes the forearms in a relaxed position on a rest, it is noted they are rolled slightly outward. Thus, to maximize the support of a flat surface, the forearms must be rotated inward placing undue stress on the wrist and forearm which is transmitted to the upper arm and shoulder causing fatigue. The outward slope and surface area design of the present invention, however, conform to the natural resting curve of the forearm. The angle of the slope away from the centerline conforms to the position the forearms assume when the hands move to the center of the keyboard. Furthermore, as the hands of the keyboard user move across the keyboard and the forearms roll or rotate, the wider surface area of the sloping surface at the forward portion continuously supports the broader surface of the user's forearms during such rotation, thereby maximizing the support of the forearms and reducing fatigue of the upper arms and shoulders.